drivers/scsi/scsi_dh.c

   1 /*
   2  * SCSI device handler infrastruture.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the
   6  * Free Software Foundation; either version 2 of the License, or (at your
   7  * option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * Copyright IBM Corporation, 2007
  19  *      Authors:
  20  *               Chandra Seetharaman <sekharan@us.ibm.com>
  21  *               Mike Anderson <andmike@linux.vnet.ibm.com>
  22  */
  23
  24 #include <linux/slab.h>
  25 #include <linux/module.h>
  26 #include <scsi/scsi_dh.h>
  27 #include "scsi_priv.h"
  28
  29 static DEFINE_SPINLOCK(list_lock);
  30 static LIST_HEAD(scsi_dh_list);
  31
  32 struct scsi_dh_blist {
  33         const char *vendor;
  34         const char *model;
  35         const char *driver;
  36 };
  37
  38 static const struct scsi_dh_blist scsi_dh_blist[] = {
  39         {"DGC", "RAID",                 "emc" },
  40         {"DGC", "DISK",                 "emc" },
  41         {"DGC", "VRAID",                "emc" },
  42
  43         {"COMPAQ", "MSA1000 VOLUME",    "hp_sw" },
  44         {"COMPAQ", "HSV110",            "hp_sw" },
  45         {"HP", "HSV100",                "hp_sw"},
  46         {"DEC", "HSG80",                "hp_sw"},
  47
  48         {"IBM", "1722",                 "rdac", },
  49         {"IBM", "1724",                 "rdac", },
  50         {"IBM", "1726",                 "rdac", },
  51         {"IBM", "1742",                 "rdac", },
  52         {"IBM", "1745",                 "rdac", },
  53         {"IBM", "1746",                 "rdac", },
  54         {"IBM", "1813",                 "rdac", },
  55         {"IBM", "1814",                 "rdac", },
  56         {"IBM", "1815",                 "rdac", },
  57         {"IBM", "1818",                 "rdac", },
  58         {"IBM", "3526",                 "rdac", },
  59         {"IBM", "3542",                 "rdac", },
  60         {"IBM", "3552",                 "rdac", },
  61         {"SGI", "TP9",                  "rdac", },
  62         {"SGI", "IS",                   "rdac", },
  63         {"STK", "OPENstorage",          "rdac", },
  64         {"STK", "FLEXLINE 380",         "rdac", },
  65         {"STK", "BladeCtlr",            "rdac", },
  66         {"SUN", "CSM",                  "rdac", },
  67         {"SUN", "LCSM100",              "rdac", },
  68         {"SUN", "STK6580_6780",         "rdac", },
  69         {"SUN", "SUN_6180",             "rdac", },
  70         {"SUN", "ArrayStorage",         "rdac", },
  71         {"DELL", "MD3",                 "rdac", },
  72         {"NETAPP", "INF-01-00",         "rdac", },
  73         {"LSI", "INF-01-00",            "rdac", },
  74         {"ENGENIO", "INF-01-00",        "rdac", },
  75         {NULL, NULL,                    NULL },
  76 };
  77
  78 static const char *
  79 scsi_dh_find_driver(struct scsi_device *sdev)
  80 {
  81         const struct scsi_dh_blist *b;
  82
  83         if (scsi_device_tpgs(sdev))
  84                 return "alua";
  85
  86         for (b = scsi_dh_blist; b->vendor; b++) {
  87                 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
  88                     !strncmp(sdev->model, b->model, strlen(b->model))) {
  89                         return b->driver;
  90                 }
  91         }
  92         return NULL;
  93 }
  94
  95
  96 static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
  97 {
  98         struct scsi_device_handler *tmp, *found = NULL;
  99
 100         spin_lock(&list_lock);
 101         list_for_each_entry(tmp, &scsi_dh_list, list) {
 102                 if (!strncmp(tmp->name, name, strlen(tmp->name))) {
 103                         found = tmp;
 104                         break;
 105                 }
 106         }
 107         spin_unlock(&list_lock);
 108         return found;
 109 }
 110
 111 static struct scsi_device_handler *scsi_dh_lookup(const char *name)
 112 {
 113         struct scsi_device_handler *dh;
 114
 115         if (!name || strlen(name) == 0)
 116                 return NULL;
 117
 118         dh = __scsi_dh_lookup(name);
 119         if (!dh) {
 120                 request_module("scsi_dh_%s", name);
 121                 dh = __scsi_dh_lookup(name);
 122         }
 123
 124         return dh;
 125 }
 126
 127 /*
 128  * scsi_dh_handler_attach - Attach a device handler to a device
 129  * @sdev - SCSI device the device handler should attach to
 130  * @scsi_dh - The device handler to attach
 131  */
 132 static int scsi_dh_handler_attach(struct scsi_device *sdev,
 133                                   struct scsi_device_handler *scsi_dh)
 134 {
 135         int error, ret = 0;
 136
 137         if (!try_module_get(scsi_dh->module))
 138                 return -EINVAL;
 139
 140         error = scsi_dh->attach(sdev);
 141         if (error != SCSI_DH_OK) {
 142                 switch (error) {
 143                 case SCSI_DH_NOMEM:
 144                         ret = -ENOMEM;
 145                         break;
 146                 case SCSI_DH_RES_TEMP_UNAVAIL:
 147                         ret = -EAGAIN;
 148                         break;
 149                 case SCSI_DH_DEV_UNSUPP:
 150                 case SCSI_DH_NOSYS:
 151                         ret = -ENODEV;
 152                         break;
 153                 default:
 154                         ret = -EINVAL;
 155                         break;
 156                 }
 157                 if (ret != -ENODEV)
 158                         sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
 159                                     scsi_dh->name, error);
 160                 module_put(scsi_dh->module);
 161         } else
 162                 sdev->handler = scsi_dh;
 163
 164         return ret;
 165 }
 166
 167 /*
 168  * scsi_dh_handler_detach - Detach a device handler from a device
 169  * @sdev - SCSI device the device handler should be detached from
 170  */
 171 static void scsi_dh_handler_detach(struct scsi_device *sdev)
 172 {
 173         sdev->handler->detach(sdev);
 174         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
 175         module_put(sdev->handler->module);
 176 }
 177
 178 void scsi_dh_add_device(struct scsi_device *sdev)
 179 {
 180         struct scsi_device_handler *devinfo = NULL;
 181         const char *drv;
 182
 183         drv = scsi_dh_find_driver(sdev);
 184         if (drv)
 185                 devinfo = __scsi_dh_lookup(drv);
 186         /*
 187          * device_handler is optional, so ignore errors
 188          * from scsi_dh_handler_attach()
 189          */
 190         if (devinfo)
 191                 (void)scsi_dh_handler_attach(sdev, devinfo);
 192 }
 193
 194 void scsi_dh_release_device(struct scsi_device *sdev)
 195 {
 196         if (sdev->handler)
 197                 scsi_dh_handler_detach(sdev);
 198 }
 199
 200 /*
 201  * scsi_register_device_handler - register a device handler personality
 202  *      module.
 203  * @scsi_dh - device handler to be registered.
 204  *
 205  * Returns 0 on success, -EBUSY if handler already registered.
 206  */
 207 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 208 {
 209         if (__scsi_dh_lookup(scsi_dh->name))
 210                 return -EBUSY;
 211
 212         if (!scsi_dh->attach || !scsi_dh->detach)
 213                 return -EINVAL;
 214
 215         spin_lock(&list_lock);
 216         list_add(&scsi_dh->list, &scsi_dh_list);
 217         spin_unlock(&list_lock);
 218
 219         printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
 220
 221         return SCSI_DH_OK;
 222 }
 223 EXPORT_SYMBOL_GPL(scsi_register_device_handler);
 224
 225 /*
 226  * scsi_unregister_device_handler - register a device handler personality
 227  *      module.
 228  * @scsi_dh - device handler to be unregistered.
 229  *
 230  * Returns 0 on success, -ENODEV if handler not registered.
 231  */
 232 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 233 {
 234         if (!__scsi_dh_lookup(scsi_dh->name))
 235                 return -ENODEV;
 236
 237         spin_lock(&list_lock);
 238         list_del(&scsi_dh->list);
 239         spin_unlock(&list_lock);
 240         printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
 241
 242         return SCSI_DH_OK;
 243 }
 244 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
 245
 246 /*
 247  * scsi_dh_activate - activate the path associated with the scsi_device
 248  *      corresponding to the given request queue.
 249  *     Returns immediately without waiting for activation to be completed.
 250  * @q    - Request queue that is associated with the scsi_device to be
 251  *         activated.
 252  * @fn   - Function to be called upon completion of the activation.
 253  *         Function fn is called with data (below) and the error code.
 254  *         Function fn may be called from the same calling context. So,
 255  *         do not hold the lock in the caller which may be needed in fn.
 256  * @data - data passed to the function fn upon completion.
 257  *
 258  */
 259 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 260 {
 261         struct scsi_device *sdev;
 262         int err = SCSI_DH_NOSYS;
 263
 264         sdev = scsi_device_from_queue(q);
 265         if (!sdev) {
 266                 if (fn)
 267                         fn(data, err);
 268                 return err;
 269         }
 270
 271         if (!sdev->handler)
 272                 goto out_fn;
 273         err = SCSI_DH_NOTCONN;
 274         if (sdev->sdev_state == SDEV_CANCEL ||
 275             sdev->sdev_state == SDEV_DEL)
 276                 goto out_fn;
 277
 278         err = SCSI_DH_DEV_OFFLINED;
 279         if (sdev->sdev_state == SDEV_OFFLINE)
 280                 goto out_fn;
 281
 282         if (sdev->handler->activate)
 283                 err = sdev->handler->activate(sdev, fn, data);
 284
 285 out_put_device:
 286         put_device(&sdev->sdev_gendev);
 287         return err;
 288
 289 out_fn:
 290         if (fn)
 291                 fn(data, err);
 292         goto out_put_device;
 293 }
 294 EXPORT_SYMBOL_GPL(scsi_dh_activate);
 295
 296 /*
 297  * scsi_dh_set_params - set the parameters for the device as per the
 298  *      string specified in params.
 299  * @q - Request queue that is associated with the scsi_device for
 300  *      which the parameters to be set.
 301  * @params - parameters in the following format
 302  *      "no_of_params\0param1\0param2\0param3\0...\0"
 303  *      for example, string for 2 parameters with value 10 and 21
 304  *      is specified as "2\010\021\0".
 305  */
 306 int scsi_dh_set_params(struct request_queue *q, const char *params)
 307 {
 308         struct scsi_device *sdev;
 309         int err = -SCSI_DH_NOSYS;
 310
 311         sdev = scsi_device_from_queue(q);
 312         if (!sdev)
 313                 return err;
 314
 315         if (sdev->handler && sdev->handler->set_params)
 316                 err = sdev->handler->set_params(sdev, params);
 317         put_device(&sdev->sdev_gendev);
 318         return err;
 319 }
 320 EXPORT_SYMBOL_GPL(scsi_dh_set_params);
 321
 322 /*
 323  * scsi_dh_attach - Attach device handler
 324  * @q - Request queue that is associated with the scsi_device
 325  *      the handler should be attached to
 326  * @name - name of the handler to attach
 327  */
 328 int scsi_dh_attach(struct request_queue *q, const char *name)
 329 {
 330         struct scsi_device *sdev;
 331         struct scsi_device_handler *scsi_dh;
 332         int err = 0;
 333
 334         sdev = scsi_device_from_queue(q);
 335         if (!sdev)
 336                 return -ENODEV;
 337
 338         scsi_dh = scsi_dh_lookup(name);
 339         if (!scsi_dh) {
 340                 err = -EINVAL;
 341                 goto out_put_device;
 342         }
 343
 344         if (sdev->handler) {
 345                 if (sdev->handler != scsi_dh)
 346                         err = -EBUSY;
 347                 goto out_put_device;
 348         }
 349
 350         err = scsi_dh_handler_attach(sdev, scsi_dh);
 351
 352 out_put_device:
 353         put_device(&sdev->sdev_gendev);
 354         return err;
 355 }
 356 EXPORT_SYMBOL_GPL(scsi_dh_attach);
 357
 358 /*
 359  * scsi_dh_attached_handler_name - Get attached device handler's name
 360  * @q - Request queue that is associated with the scsi_device
 361  *      that may have a device handler attached
 362  * @gfp - the GFP mask used in the kmalloc() call when allocating memory
 363  *
 364  * Returns name of attached handler, NULL if no handler is attached.
 365  * Caller must take care to free the returned string.
 366  */
 367 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
 368 {
 369         struct scsi_device *sdev;
 370         const char *handler_name = NULL;
 371
 372         sdev = scsi_device_from_queue(q);
 373         if (!sdev)
 374                 return NULL;
 375
 376         if (sdev->handler)
 377                 handler_name = kstrdup(sdev->handler->name, gfp);
 378         put_device(&sdev->sdev_gendev);
 379         return handler_name;
 380 }
 381 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);